1. Technical Field
The present invention relates generally to a semiconductor integrated circuit, and more particularly to a page buffer structure of a semiconductor memory apparatus.
2. Related Art
With the development of a mobile system, demand for semiconductor memory devices such as nonvolatile memory devices increases.
A flash memory device which is a nonvolatile memory device capable of electrically erasing and programming data may maintain data even in absence of power supply. Furthermore, the flash memory device has low power consumption and high access time characteristics.
The flash memory device is divided into a NOR type and a NAND type depending on the configuration of cells and bit lines. In particular, since the NAND flash memory device has a string structure in which a plurality of cell transistors are coupled in series to a bit line, the NAND flash memory may store a large amount of data in a relatively small area.
However, with the trend of high capacity and high integration, the flash memory device also has many limits on a cell area and a chip size.